[英]Sum of two calculated columns in SQL
我正在計算兩行,如下所示:
CASE
WHEN isnumeric(SUBSTRING(dbo.Table.RNumber,1,CHARINDEX('+',dbo.Table.RNumber) - 1)) = 1
THEN SUBSTRING(dbo.Table.RNumber,1,CHARINDEX('+',dbo.Table.RNumber) - 1)
else 0
end AS RoomNumber,
CASE
WHEN isnumeric(SUBSTRING(dbo.Table.R.Number,CHARINDEX('+',dbo.Table.RNumber) + 1,LEN(dbo.Table.R.Number))) = 1
THEN SUBSTRING(dbo.Table.R.Number,CHARINDEX('+',dbo.Table.RNumber) + 1,LEN(dbo.Table.R.Number))
else 0
end AS HallNumber,
我需要創建另一個列來計算RoomNumber和HallNumber的總和,我試過這個:
SELECT *, (RoomNumber + HallNumber) AS Sum
FROM Table
但我得到了無效的列名錯誤。 我怎樣才能得到這兩列的總和? 謝謝。
您實際上只有兩個選項,因為您無法在定義它的同一級別重用別名。 您可以將兩個CASE
語句加在一起:
CASE WHEN isnumeric(SUBSTRING(dbo.Table.RNumber,1,CHARINDEX('+',dbo.Table.RNumber) - 1)) = 1
THEN SUBSTRING(dbo.Table.RNumber,1,CHARINDEX('+',dbo.Table.RNumber) - 1)
ELSE 0 END AS RoomNumber,
CASE WHEN isnumeric(SUBSTRING(dbo.Table.R.Number,CHARINDEX('+',dbo.Table.RNumber) + 1,LEN(dbo.Table.R.Number))) = 1
THEN SUBSTRING(dbo.Table.R.Number,CHARINDEX('+',dbo.Table.RNumber) + 1,LEN(dbo.Table.R.Number))
ELSE 0 END AS HallNumber,
(CASE WHEN isnumeric(SUBSTRING(dbo.Table.RNumber,1,CHARINDEX('+',dbo.Table.RNumber) - 1)) = 1
THEN SUBSTRING(dbo.Table.RNumber,1,CHARINDEX('+',dbo.Table.RNumber) - 1)
ELSE 0 END
+
CASE WHEN isnumeric(SUBSTRING(dbo.Table.R.Number,CHARINDEX('+',dbo.Table.RNumber) + 1,LEN(dbo.Table.R.Number))) = 1
THEN SUBSTRING(dbo.Table.R.Number,CHARINDEX('+',dbo.Table.RNumber) + 1,LEN(dbo.Table.R.Number))
ELSE 0 END) AS Sum
或者,您可以嘗試將當前查詢包裝為子查詢,其中您已定義的別名可用:
SELECT t.RoomNumber,
t.HallNumber,
(t.RoomNumber + t.HallNumber) AS Sum
FROM
(
... your original query ...
) t
您需要子查詢來匯總計算列。
SELECT a.*, (a.RoomNumber + a.HallNumber) AS Sum
(SELCT CASE
WHEN isnumeric(SUBSTRING(dbo.Table.RNumber,1,CHARINDEX('+',dbo.Table.RNumber) - 1)) = 1
THEN SUBSTRING(dbo.Table.RNumber,1,CHARINDEX('+',dbo.Table.RNumber) - 1)
else 0
end AS RoomNumber,
CASE
WHEN isnumeric(SUBSTRING(dbo.Table.R.Number,CHARINDEX('+',dbo.Table.RNumber) + 1,LEN(dbo.Table.R.Number))) = 1
THEN SUBSTRING(dbo.Table.R.Number,CHARINDEX('+',dbo.Table.RNumber) + 1,LEN(dbo.Table.R.Number))
else 0
end AS HallNumber) AS a
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